The dangers of termites (also known as “white ants”) are well known and documented. Termites can cause major damage to buildings in a relatively short time, and it is therefore important that property owners be vigilant in detecting the presence of termites.
However, as termites live and nest underground or in concealed places, it is not normally possible to detect their presence visually. So-called “mud trails” on a surface may indicate the presence of termites, but these mud trails are normally constructed by termites in obscured places. Moreover, the absence of mud trails does guarantee that there is no termite infestation. Termites may gain access to the interior of a building through cracks in concrete slabs or through construction joints which are concealed from view. Detection of termite activity by routine visual inspection is therefore an unreliable method.
A traditional method of preventing termite infestation is to treat the soil under and/or around a building with a chemical which is toxic to termites. However, due to health and environmental concerns, highly toxic chemicals, such as organo-chlorides, have now been phased out and the permitted chemicals are far less effective and have a much shorter active life.
Physical termite barriers such as stainless steel mesh are relatively expensive, and may lead to a false sense of security since these barriers are known to fail. Even a small crack is sufficient to permit termites to enter and infest a building.
It is also known to use “bait stations” positioned around a building. These bait stations contain a food, such as cardboard, which is attractive to termites. The bait stations need to be checked manually on a regular basis. If termite activity is noticed, the bait may be replaced by a toxic bait which, hopefully, is taken to the termite nest by the termites to kill the colony. However, such toxic baits often fail to destroy the entire colony. The surviving termites can establish a new colony in a different location close to the building, from which they can infest the building. Furthermore, the checking of bait stations is time consuming and tedious, and must be conducted frequently in order to obtain early indication of termite activity.
Electronic termite baits have been developed to generate signals when termite activity is detected. These signals can be used to trigger an alarm. A plurality of electronic baits can be connected to a central control station, so that multiple baits can be continually monitored. Examples of such electronic termite baits can be found in international patent application no. PCT/AU02/01201, U.S. Pat. Nos. 6,052,066, 5,815,090, 5,571,967 and U.S. patent application 2002/0144452.
The termite detection systems described in the abovementioned patents generally require the termites to eat through some edible bait or conductive metal to trigger a mechanical or electrical switch or flag. Such systems are not always reliable or effective. For example, it may take some time for the termites to eat through the bait or conductive metal, during which time substantial damage may be done to the building by other termites. In some cases, the bait or conductive metal may not be eaten through completely, and the mechanical or electrical switch or flag may not be triggered. Detectors which rely on termites eating through metal conductors are unreliable, as the termites might elect not to eat the metal when there is more easily digested food available.
U.S. patent application 2002/0144452 discloses a termite detection system which uses a microchip to detect the sound made by termites. It is believed that this system would be impractical since, depending on its sensitivity, the microchip might fail to detect the sounds made by termites or may generate many false alarms triggered by extraneous sounds, thereby rendering the system unreliable.
It is an aim of this invention to provide method and apparatus for detecting the presence of termites, which overcome or ameliorate one or more of the disadvantages or problems described above, or at which at least provide the consumer with a useful choice.